Magnetic recorder



llg- 11, 1953 c. N. HlcKMAN 2,648,589

MAGNETIC RECORDER Filed July 19, 1949 WCUUM C. N CKMAN 42 40 39 f READ/Na c/ncu/r A 7- op/VE V Patented Aug. 1'1, 1953 MAGNETIC RECORDER Clarence N. Hickman, Jackson Heights, N. Y., assignor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application July 19, 1949, Serial No. 105,542

Claims.

The present invention relates to electromagnetic apparatus, and more particularly to an apparatus for either recording or reading data across an elongated magnetizable element instead of lengthwise thereof.

In certain applications of magnetic recording such as, for example, in telephone message accounting, it is desirable when reproducing a record or any portion thereof from one magnetic medium to another, to have the information recorded across the original medium. To this end I have devised an apparatus one of Whose features is an arrangement of parts and a control circuit therefor for moving the medium lengthwise of the movement of the recording or reading magnet, but periodically stopping the medium while the magnet moves across the medium for recording or other purposes,

This and other features of the invention will be more clearly understood from the following description, attached claims and appended drawing in which:

Fig. l shows an isometric view of one form of the apparatus, with parts of the enclosing frame cut away t0 expose the elements of the arrangement;

Fig. 2 shows a modified form of the apparatus, while Fig. 3 shows schematically portions of the controlling circuit, including certain elements not disclosed in but forming a part of the apparatus shown in Fig. 1 and Fig. 2.

Referring to Fig. 1, the magnetic element or medium 3, which may be a magnetically coated paper or plastic film or other suitable magnetizable material, is supported upon two pairs of sprocket wheels, one pair of driving wheels 2 Xed on the shaftl' rotatably secured to frame 3U, and a pair of idler wheels l xed on the shaft 20 also rotatably secured to frame 30. The sprocket wheels on both shafts are suitably spaced and aligned to cause the teeth thereof to pass through feed holes provided along both edges of the medium 3. Between its two supports, said medium 3 passes over the drum 1 and is made to conform to the surface of the latter by the superposed pneumatic chamber 3l or other suitablev means. The drum 1 is mounted upon shaft 8 and is constantly rotated by a motor (not shown) or by any other suitable source of power. A variable pitch worm 9 is also mounted on shaft 8 in engageable relation with the worm wheel as described below. The thread of the worm 9 is divided into four sectors, namely, a zero pitch sector, a constant acceleration pitch sector, a

constant Velocity pitch sector, and a constant deceleration pitch sector.

Mounted at the left end of shaft i2 in engageable relation to the worm e is the worm wheel l0, while at the right end of said shaft is mounted the gear wheel i3 in constant mesh with gear wheel Il mounted at the forward end of shaft I8 upon which, as previously stated, is also mounted the pair of driving sprocket wheels 2 in spaced relation to pass through the feed holes of the medium 3. Shaft l2, together with worm Wheel l0 and gear wheel I3, are mounted on the bracket I4 which is pivoted about the pin 35 in the plane of the gears I3 and Il. Bracket I4 is provided with a lip l5 of magnetic material which acts as an armature for the double-wound relay I6, the latter being mounted upon a support secured to the frame 3B. The bracket I4 is supported at its other end by retractile spring 36 hooked to the extension piece 32 secured to or forming a part of the frame 3B, The rod 33 is also secured to the frame 3S and is lodged under but clear of the shaft i8 to support the upper end of bracket I against the tension of spring 36.

When relay I6 is energized as subsequently described, the bracket I4 pivots to the left about the pin 35, that is, moves counterclockwise, enabling worm wheel Il] to engage the worm 9. As previously stated, the worm S has a variable pitch thread divided into four sectors. One sector has a zero pitch, and the purpose thereof is to impart n0 motion to the wheel l when the latter engages the worm during the length of this sector as subsequently to be described. Assuming that the shaft 8 is rotating clockwise as indicated, this zero pitch sector is followed by another pitch sector which imparts constant acceleration to the wheel I if the worm is in gear therewith. The constant acceleration sector is then followed by another pitch sector that imparts a constant velocity7 to the wheel it if in gear with the worm, and the last-mentioned sector is then followed by still another sector that imparts constant deceleration to the wheel Hl if in gear with the worm. rlhus the zero pitch sector is followed by the constant acceleration pitch sector and preceded by the constant deceleration pitch sector.

These different pitch sectors on the worm S control the amount and character of the rotation imparted to the wheel l@ when the latter is engaged with the worm 9. It is obvious that when the worm and the wheel are traversingA through the zero pitch sector of the worm, no

wheels 2 mounted thereon, causing said sprocket wheels to propel the medium 3 forward across the surface of the drum 1. For the time that the worm is rotating through its constant acceleration pitch sector, the wheel l0 is brought up to the required constant speed by the end of the sector, which speed, being communicated to the sprocket wheels 2, accelerates the movement of the medium 3 by a like amount, causing it to traverse the surface of the drum 'l at a constant velocity for the period that the wheel I0 engages the constant velocity pitch sector that follows the constant acceleration pitch sector.

During the time that the medium 3 is moving across the surface of drum at a constant velocity, the drum will be rotating to bring the magnet H back into engagement with the medium. When the worm 9 reaches the end of the constant velocity pitch sector, drum 'l will have rotated to a point where the pole face of the magnet i will be slightly distant from the remote edge of the medium. It is at this point that the worm will begin rotating through its constant deceleration pitch sector, causing decelerated motion to be imparted to wheel i6 and hence to the sprocket wheels 2, thus slowing down the movement of the medium to a stop by the time that the worm has fully traversed the length of its deceleration pitch sector, at which time, further, the magnet H will have been advanced into coincidence, or near coincidence, with the next tract in the medium. Since the deceleration pitch sector is followed by the zero velocity pitch sector, it follows that during the traversal of said last-mentioned sector, the medium will remain stationary while the magnet Il sweeps transversely across the succeeding track of the medium to record a signal thereon.

Since the intermittent movement of the medium 3 across the surface of the drum 1 depends upon maintaining wheel I3 meshed with the worm 3, and since this meshing depends upon the continued energization or relay I6 as above described, the above cycle of operations will be repeated as long as relay I6 remains operated.

When recording (or reading) operations are completed and it is desired to stop the operation of the device, relay 6 is operated in any suitable manner, which thereupon opens the locking circuit of relay I6. However, if relay 6 is operated at a time when the worm 9 is meshed with wheel l through any of its pitch sectors except the zero pitch sector, relay I6 will not release since, at this time, brush 42 will be sweeping over the conducting segment 39 of the commutator, supplying a supplementary locking circuit for relay i6 over a path traced from ground on segment 39, brush 42, resistor I', contacts of relay I6, locking winding thereof to battery. This circuit will hold relay I6 operated which, in turn, will maintain the worm 9 meshed with wheel i0 and cause the medium 3 to be advanced across the surface of the drum until the magnet I l will again be in coincidence, or near coincidence, with the next track on the medium, by which time the worm will have advanced to its zero pitch sector and brush 42 will have reached the insulating segment 43 of the commutator. The locking circuit of relay i6 will then be opened, releasing said relay. Upon the release of the relay, bracket i4 tilts upward about the pivot 35, spring 33 lifting the bracket to disengage the wheel from the worm 9 until said bracket comes to rest under pin 33. Thus in the operation of the device, the arrangement described is 6 such that wheel l0 will always engage the worin 9 on its zero velocity pitch sector, thereby insuring against the loss of recording (or reading) any signal in the medium 3 since, if relay I6 is operated to clutch the wheel l0 with the worm on this sector, the clutching takes place at the time that the pole face of magnet H is in position to record or read at the beginning of a track.

In the modification of the device shown in Fig. 2, the worm 9 is replaced by the disc 44 and certain parts of the device identified by the same numerals as in Fig. 1 are slightly modified and rearranged. The disc 44 carries a variable pitch thread divided, as is the thread of worm l0, into a zero pitch, constant velocity, constant deceleration and constant acceleration pitch sectors, and in the same order as described for the worm I0. Normally the wheel I0 is not in engagement with the thread on the disc 44, but when relay I6 is operated in the manner described, the armature l5 is attracted to pivot the bracket i 4 clockwise about the pin 35, bringing the wheel i0 into mesh with the zero pitch sector of the thread on the disc, thereby causing motion to be imparted to the gear wheels i3 and Il and to sprocket wheels 2 in accordance with the pitch of the four sectors of the thread.

While I have illustrated my invention in its application to two embodiments thereof, it is not limited to such application nor to the specific arrangements disclosed herein. It will be evident to one skilled in the art that many applications, arrangements, and modifications, other than those herein disclosed, are within the scope of the invention.

Further, the terms and expressions which I have used in reference to the invention and its elements are used as terms of description and not of limitation, and I have no intention by the use of said terms and expressions of excluding thereby equivalents of the features shown and described or portions thereof but, on the contrary, intend to include therein any and all equivalents and modications which may be employed without departing from the spirit of the invention.

What is claimed is:

1. Apparatus for moving a magnetic body successively across a plurality of tracks on a magnetic medium, comprising in combination with said medium a movable support therefor, rotating means mounting thereupon a magnetic body, a variable pitch worm, means permanently connected with said movable support and engageable with said worm, and means operative only at times to produce an engagement of said lastmentioned means with said worm, whereby unidirectional variable motion is imparted by said last-mentioned means to said movable support for advancing said medium one track.

2. Apparatus for recording signals on or reading signals from a magnetic medium, comprising in combination with a magnetic medium in a stationary position, a continuously rotating member, a magnet mounted upon said member adapted to move across said medium for recording or reading during one portion of the rotary movement of said magnet, a variable pitch device mounted upon said member, and means engageable only at times with said device for advancing said medium longitudinally during another portion of the rotary movement of said magnet.

3. Apparatus for recording signals on or read- "7 ing signals from a magnetic medium, comprising fin combination`Al withV -a magnetici lmedium -inJ i a stationaryposition, a-continuously rotating shaft, a magnet mounted upon said shaft adapted' to moveeacross'said-mediumfor recording or read- -ing--during aportion of `'tlfierota'ry Amovement -ofsaidmagnet, a'worm ldevice mounted'upon said sha-ft'having a variable pitch 'thread 'divided into .a-zero pitch sector,"aconstant l velocityfptch sector, a constant acceleration pitch"sector,^ and a constant decelerationy pitch?sector;A and; means engageable WithL'sai'deworm for-controlling the longitudinal movement `-of saidf medium, whereby l"no vmovementis imparted to :said-medium 'when `said means engage'the4 zero-"pitchlsector of -said "Wormfconstantl acceleration is imparted to# said medium -when -said vmeans "engage i the" constant acceleration pitchfsector of said: wormyconstant vvelocity is imparted' `tosaid-mdiumWhen#said means engage the4 constant 'velocity pitch sector vof said '-Wormfand constant-fdeceleration'isiimparted to lsaid mediumlwhen said means engage the constant deceleration'pitch y sector fof said Worm, said Worm being lso lmounted-upon` said shaft :that its zero f velocity pitch ysector is fin -engageable relation `With 'said last-mentioned means coincident with said magnet traversing said medium; ',Whereby'lsaidmedium'lremains in Aa stationary.' position during the'movementof sa-id magnet thereacross.

Li.V Apparatus for-recording signals on or'readingsignals from a magnetic vmedium comprising .in combination a constantly l'rotating shaft, 'a variable rpitch vvormon said shaft, -a "drum mounted lon #said lshaft, 12a supported -magnetic said magnet is not in magnetic engagement with f said medium.

5. YYApparatusffor recordingsignalsv` on or treading signals from'a magnetic medium,` comprising in combination 'with a magnetic medium in-"a stationary position, a continuously rotating lmember, a magnetA4 mounted upon said member Vadapted to -moveacross said medium for record- "ing-or'reading during one portion of the rotation of'said -magnet, a' variable pitch Adevice mounted upon said member, and means engageable with said variable pitch `device for -advancingf'said medium "longitudinally `-during *another portion of-the rotation of said magnet,l saidllastemensaidl relay said gear mechanismf-is -pvote'dto bring said gear into vphysical-relation withsad variable pi-tch device, and circuit means Jv'for operating'said relay, said means includingva coinrnutator for completing the circuitof Said relay only when said one pitch-sectorotsaid variable `pitch device is in engageable-r'elation Ywith said gear, whereby said gear 'engagesisad Avariable pitch device.

ClliARENCE'NrA HICKMAN.

:References Cited inwthehleof thisspatent UNITED STATES'PATENTS Number N ame Date 1,325,574 Nichols Dec.A 23, 1919 1,590,399 Tykocinski- Tykociner June 29,- 1926 1,635,324 Jenkins Julyf-12,-1927 1,833,339 Seufert Nov.24=,1931 1,920,969 Carpenter Aug. 8, 1933 2,127,331 Fulton Aug.16, 1938 2,209,720 kRustad `July 30, 1940 2,539,837 Howell AJan. 30, 1951 'FOREIGN' PATENTS Number Country 'Date 205,895 -Great Britain Oct.lf29, '.1923 

